header {
	display: block;
	width: 100%;
	position: fixed;
	background: blue;
	height: 30px;
	z-index: 10;
	top: 0;
	left: 0;
}

a {
	text-decoration: none;
}

header nav, .subheader div, .nav {
display: block;
margin: 0 auto;
width: 500px;
}

header nav a,header nav a:hover,header nav a:focus {
	color: white !important;
}